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    <title>ShellCheck: SC2179 – Use `array+=("item")` to append items to an array.</title>
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    <h1>SC2179 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2179">See this page on GitHub</a>
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    <h2 id="use-arrayitem-to-append-items-to-an-array">Use
<code>array+=("item")</code> to append items to an array.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2179.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">=</span><span class="va">(</span>one two<span class="va">)</span></span>
<span id="cb1-2"><a href="SC2179.html#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">+=</span>three</span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2179.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">=</span><span class="va">(</span>one two<span class="va">)</span></span>
<span id="cb2-2"><a href="SC2179.html#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">+=</span><span class="va">(</span> three <span class="va">)</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>It looks like you are trying to append a string to an array with
<code>var+=string</code>. This instead appends to the first element of
the array (equivalent to <code>var[0]+=three</code>).</p>
<p>In the problematic code, the array will therefore contain
<code>onethree</code> <code>two</code>.</p>
<p>Instead, append an array to the array with
<code>var+=( elements )</code>. This will append the new items to the
array.</p>
<p>In the correct code, it will contain <code>one</code>
<code>two</code> <code>three</code> as expected.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>If ShellCheck mistakenly thinks the variable is an array when it's
not (e.g. because the same name was used in a different context), you
can ignore this error.</p>
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    <p style='font-size: 80%'><a href="../index.html">ShellCheck</a> is a static analysis tool for shell scripts. This page is part of its documentation.</p>
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